Waters sports require balance, good motor coordination, and the use of the entire muscular system. These are difficult to achieve for persons who have undergone below-knee amputation. The existing prosthetic solutions do not provide plantar flexion of the foot, which is necessary for comfortable swimming. The goal of the project was to design a product enabling smooth foot movement and plantar flexion, based on a simple mechanism to make it widely available. The designer created a below-knee prosthesis and developed a concept for a hock joint and foot prosthesis. In his search for the best solution, he came across the mechanism of vibration isolation, normally used for isolating large industrial equipment. The product is still in development, with a prospect of implementation.